Receiving distributor



Patented Apr. 24, 1945 RECEIVING DISTRIBUTOR Richard E. Mathes, Silver Spring, Md., assigner to Radio Corporationof America, a corporation of Delaware application Mayl 3, 1943, serial No. 485,477

6 Claims.

`a distributor, and to provide means for maintaining synchronism between the distributor section which handles a particular train'independently of the synchronism which may be necessary with respect to a different train of signals.

One of the advantages of my invention may be appreciated by those skilled in .the art when it is understood that ina network of .radio channels extending over a wide territory and having a multiplicity of point-to-point circuits, some of the receiving stations may have insuilicient traic to warrant the maintenance of a complete multiplex system. Nevertheless, each station should be equipped with means for receiving messages from a number of diierent outlying transmitting stations. Such messages are preferably routed as far as possible through stations between which the tra-flic is sufciently heavy for continuous operation of a multiplex system, and the multiplex station nearest the destination of a given message is used to automatically repeat that message over a single channel to a station which ordinarily handles a smaller volume of traino. It is with the idea of selecting trains of signals out of diierent independent multiplex circuits and /or extending these signals over partial multiplex circuits that my invention is found t be conveniently applied.

In another practical application of my invention distributor means are provided at a given receiving station whereby a plurality of messages may be received simultaneously over different communication channels which are independent of each other, and between which it is required to maintain only au approximate synchronism.

Accordingly, it is an object of my invention to provide receiving station facilities for simultaneous reception of code signals from a plurality of independent multiplex transmitters.

It is another object of my invention to provide receiving distributor apparatus at a telegraph station which shall be conveniently operable to receive signals from different radio channels either simultaneously or successively.

It is still another object of my invention to provide a suitable distributor unit capable of maintaining synchronism of diierent receiving printers, each with a selected one of a plurality of incoming trains of signals, where the trains themselves are not necessarily synchronized with each other.

Still another object o my invention is to provde means for causing each of a plurality of incoming signal trains to control the phasing of a distributor section in a multiplex distributor unit so that the signals of the diierent trains may be independently re-shaped and fed to appropriate utilization devices such as a receiving printer, or incertain cases a relaying device including a retransmitter.

My invention will now be described in more detail, reference being made to the accompanying drawing, in which:

Fig. 1 shows diagrammatically a circuit arrangement comprising various units which may be used simultaneously and/or independently for reception of diierent trains of code signals;

Fig. 2 shows an elevation view looking at a preferred embodiment of my receiving distributor unit;

Fig. 3 shows a face View of a brush-carrying rotor which forms part of the receiving distributor; and

Fig. 4 shows a face view oi a Contact cam of the so-called rkicker type against opposite faces of which two brushes are applied while two other brushes bear against the periphery. At least three of these brushes are rotatably mounted on the brush-carrying member shown in Fig. 3.

Referring rst to Fig. l, I show therein three amplifier-rectifier units i, 2, and`3, each of which is arranged to accept incoming telegraph code signals. Different receivers (not shown) may be used to select the separate signal trains arriving from different transmitters and to apply them individually to appropriate'ones of the amplierrectier units i, 2, and 3. On the output side of these units are circuits leading to ground and to independent brushes 4, 5, and 6 which contact ,with collector rings 'l on the rotors i8, 38, 58 of a receiving kicker.

In multiplex systems as developed for radio use, it is the common practice to select a very small portion of the incoming signals as near as possible to the center of a baud unit for detectingwhether it is of marking or spacing signicance. The moment of passage of a conductive segment in the kicker rotor iii beneath a brush determines the moment when this kicker action shall take place. If atthat instant a marking signal is present, it will be picked up by the brush and passed through a. so-called locking circuit whereby the signal eiects may be substantially elongated for use in a recorder or printer. Locking circuits for this purpose are well known in the art and are exempliiied by Patent No. 1,844,950, granted February 16, 1932, to J. L. Finch.

Each of the collector rings 1 is mounted on a disk of insulating material I8, 38, 58. Each of these disks possesses a hub 9 which is keyed by means of a set screw I on a shaft II, the latter being coupled to and coaxial with the rotor oi a synchronous motor I2. The shaft II may, if desired, be journaled in bearings I3 at least at one end. This arrangement is best observed in Fig. 2.

Although the brushes 4, 5, and B may bestationarily mounted in any convenient manner, it is essential that other brushes such as I4, I5, and I6 be rotatably mounted so that they may be phased by' a correction motor I1 with respect to the incoming signals. The means for applying correction are well known in the art. Reference is made to my patents, No. 2,298,220, granted October 6, 1942; No. 2,038,375, granted April 21, i936;- and No. 2,221,447, granted August 2U, 1940. In these patents the phase correction ofr synchronous distributors is fully explained. A more recent development of phase correctors for telegraph systems is shown and described in vPatent No. 2,252,364 which was granted August 12, 1941, to G. R. Clark. His patent describes electronic means for distributor phase correction, andsuch means may well be used to control the correction motors I1, 31, and 51 as shown in the instant application, Figs. 1 and 2.

On the shaft of the correction motor I1 is a worm 158 which meshes with a worm wheelv I9. This worm wheel is arranged to carry the brushes I4, I5, and I6 in cooperative relation with one face and the periphery of the disk I8. Brush I4 is used to connect the incoming signal circuit to the input side of a locking circuit 20. Brushes I5 and I6 whichbear on the periphery ofthe disk I8 are used to control one of the correction units 8. On the output side of the correction unit are circuits leading to the correction motor I1 and arranged to drive this motor reversibly in dependence upon the lead or lag of the signals with resulnciently for these brushes to be rephased.

Correspondingly, if the worm wheel I9 needs to be rotated in the opposite direction, then a marking impulse would be applied to brush I6 and the correction unit 8 will operate' reversibly to drive the motor l1 in the proper direction' for re-adjus'tment of the phase.

Since the Worm wheel I9 may be rotated from time to time and through any angle' such as may be required for maintenance of the proper phase relation of the brushes with respect to the incoming signals, it is necessary to employ collector rings 23, 24, and 25, each insulated from the other and from the metallic portion of the worm wheel I9 so that the correction impulses and the useful signal impulses may be taken on and carried through the proper'circuits 26, 21, and 28.

Since the distributor section which comprises disk I8 and worm wheel I9, together with their collector rings and brushes are exactly duplicated in other sections of the receiving distributor, it is unnecessary to mention they duplicated parts in these other sections, or to describe how they operate. Each section is dependent on the others except for the fact that the disks I8, 38, and 58 are all keyed to the shaft II and rotate at the speed of the motor I2. On the other hand, the

brush holders i9, 39, and 59 carry diierent sets of brushes and: are made orientable by means of different correction motors I'l, 31, and 51, which rotate their respective worms e8, the latter meshing individually with worm gears on the peripheries-'of the brush holders I9, 39, 59. Thus different trains of incoming signals are applied to these distributor sections independently of the other'. f

. ,It will belunderstood that a local alternating current vpower source, the frequency of whichis well regulated, is 4used for driving the motor I2. The function of the correction motors IT, 31, and $1 is to correct for slight differences between the frequency' of this power source and the correvspendingv frequency which is used for transmit-` ting the incoming signals. Usually frequency standards are available which maintain the proper speed of a synchronous motor-driven distributor within a ratio of l/`100,000. However, these slight departures must be compensated by corrective means such as herein shown.

In the operationsof my' improved receiving distributor, the incoming signals derived from different' radio channels and applied asv separate trains to the amplier-rectifiers l, 2, and 3 are fed thereby after rectification -into individual distributor sections. The circuits through one section, for example, lead out on conductor 26 to a locking circuit 20 and `out on conductors 21 and 28ftol the correction unit 8. The output from the locking circuit 2t may be fed to a printer et'.

While the printer 30 is in operation on channel another 'printer 3l may be arranged to receive signals from channel B, these signals being fed through the distributor section which includes kicker disk 38 and the brush holder. 39.

The number of distributor sections which may b'e provided' is not limited, but in the drawing I show three of these sections by way of illustration. Also in the third section, I have shown the possibility for channel extension by means of a delay unit 50 on the output side of the locking circuit 40; This delay unit may, for example, be of the type shown and described in Patent No. 2,270,449, granted January 20, 1942, to. A. Kahn. The purpose of the delay unit is to enable the retransmitted signals as keyed by a unit 5I to be fed into an outgoing multiplex channel along vwith other trains of signals from different multiplex keyers.

From the foregoing description of the means .preferably employed and the mode of operation of my invention, it will be seen that many advantages are to be derived from the use of an integrated receiving distributor having a plurality of sections', each equipped with a kicker rotor and a set of orientable brushes. Various modifications of the invention will doubtless suggest themselves to those skilled in the art, yet these modifications would be comprehended within the scope of the invention.

I claim:

1. In an electrical distributor, a, plurality of brush holders, a shaft on which said holders are independently swiveled, reversible motor means geared to each of said holders for independently orienting the same, a plurality of contact members each keyed to said shaft and rotatable therewith, at least one brush mounted on each of said holders and arranged to Wipe over a surface of one of said contact members respectively, collector rings on said holders and on said contact members for inclusion in the circuits of said distributor, and a motor for driving said shaft and its contact members at a substantially constant speed.

2. The combination according to claim 1 and including phase corrector means under control of incoming signals for so actuating said reversible motor means as to independently orient each brush holder and its brush with respect to the phase of the associated contact member at the instant of arrival of a, signal impulse whichis of a train applicable thereto.

3. In combination, a, unitary drive shaft having a plurality of contact members mounted for rotation therewith, a corresponding plurality of brush holders each freely swiveled on said shaftand disposed adjacent a respective one of said contact members, signal circuits individual to each contact member, brushes mounted on each brush holder and cooperatively engaged with the adjacent contact member, a motor for rotating said shaft and the contact members at a substantially constant speed, correction circuits utilization devices each in circuit with a thirdA brush on a, respective brush holder, and means including reversible phase correction motors operable in response to impulses passed through different single brushes of said brush pairs for shifting the orientation of said brush holders individually, thereby to feed the signals synchronously to their respective utilization devices.

4. The combination of claim 3 with worm and worm-gear transmission units each for effecting orientation of an appropriate brush holder by its correction motor.

5. A unitary signal regenerating system for simultaneous reception of code signals from a plurality of independent sources, said system comprising a plurality of rotary contact elements each arranged to control the instant of application of an incoming signal pulse to a locking circuit, there being an individual locking circuit for each incoming signal train, a common drive shaft on which said contact elements are mounted, each contact element having a set of brushes engaged therewith, a brush holder for each brush set, said brush holders being independently swiveled on said shaft, and phase adjusting means operable by incoming signals to re-orient each brush holder upon departure from synchronism between the rotation speed of said shaft and the periodicity of a given train of incoming signals.

6. A system according to claim 5 and including in said phase adjusting means reversible motors each geared to a respective brush holder, an electronic correction circuit under control of signal impulses which traverse a given one of said contact elements, and means responsive to the functioning of said correction circuit for applying power individually to the proper correction motor for producing said re-orientation of the brush holder.

RICHARD E. MATHES. 

